Underfeed furnace



A. HfBLACKBURN.

UNDERFEED FURNACE.

. APPLICATION FILED APR.2 1,404,569.

Patented Jan. 24, 1922 hETS-SHEET I.

A. H. BLACKBURN.

UNDERFEED FURNACE.

APPLICATION FILED APR. 22. 1918.

1,404,569. Patented Jan. 24,1922.

' 2 SHEETSSHEET 2.

189 5 0 x 1/ &8 ll 4 1/ w 26 J 15 31 35 I I 29 .j[-- 21 55 5 5i 5 9 gj I 32 J1 2.9 /35 11 v lnvenTT Maw QMn/r em mw m M UITED STATES TENT FFICE.

OF NEW JERSEY.

ILLINOIS, ASSIG-NOR TO THE UNDER CHICAGO, ILLINOIS, A CORPDRATION UNDERFEED FURNACE.

Specification of Letters Patent.

Patented Jan 24, 1922.

Application filed April 22, 1918. Serial No. 229,987.

T 0 all whom it may concern:

Be it known that I, ARTHUR H. BLAcK- BURN, a subject of the King of Great Britain, residing at Downers Grove, in the county of Du Page and State of Illinois, have invented certain new and useful Improvements in Underfeed Furnaces, of which the following is a specification.

My invention relates to improvements in underfeed furnaces and has for its object to prevent or minimize adhesion of clinkers to the portions of the fire-box floor and side walls of the combustion chamber that are laterally beyond the retorts. Other objects of my invention are to provide simple, efficient, rugged and easily renewable parts for use to the stated end, and the invention consists in the features of construction of correlation and arrangement of parts hereinafter described and claimed.

In the accompanying drawings 1 have illustrated a single embodiment of my in vention in a practically satisfactory form, but it will be understood by those skilled in the art that many changes in details of construction and arrangement may be made without departure from the spirit and scope of my invention, and that while 1 herein describe and claim some specific features of construction for their particularadvantage, my invention in its broader aspects is not limited to the details of the single embodiment shown.

in the drawings Fig. l is a-sectional perspective view illustrating schematically the general structural features of a well-known type of underfeed furnace in which my invention has been embodied; Fig. 2 is a transverse section through a portion of the furnace; and Fig. 3 is a broken section, the upper portion of which is taken on the line 3-3 of Fig. 2 and the lower portion of which is broken away on lines H and 55.

Between the side walls 10, 10 there spans the floor construction 11 of the combustion space 12, separating the latter from the wind chamber 13 to which air is supplied under pressure in accordance with. the wel -known underfeed furnace practice. 1% indicate retorts of suitable construction, a plurality being provided, of which I he outer ones extreme retorts illiifilBiOC:

tween the mean retorts above and over which air is supplied through the tuventionis not concerned. The construction shown in these particulars is schematic only.

It is well known that one drawback to the operation of these underfeed furnaces is due to the fact that as alive coal is forced upward and spills laterally from the retorts, it tends to clinker along the portions of the side walls and furnace fioor flanking the extreme retorts, especially in the zone just above the level of the main tuyere blocks 15, where combustion is very active, the clink; ers adhering to these furnace parts and making adequate cleaning a matter of difficulty as well as tending to retard the feed along the extreme retorts. It is to obviate this disadvantage that my invention is employed. By providing dead plates to extend from the extreme retorts to the adjacent side walls, preferably in sloping position inclinin upwardly from the retorts, making passagesextending along the undersides of these plates from intake points adjacent the furnace side walls and communicating with the wind chamber 18 below the retorts, and providing air escape openings or tuyeres leading to the combustion chamber at the inner ends of these plates, 1 insure a circulation of air laterally below the dead plates that keeps them adequately cool to prevent the adhesion of clinkers thereto. in the specific construction shown these air cooled dead plates are employed in conjunction with wind boxes embedded in the side walls of the furnace, such wind boxes being themselves partitioned to provide an air directive channel open at its intake end to the wind chamber below the retorts and at its eduction end openingto the intake end of the dead plate passages. These side wall 4 erably have their face plates ertenaing above the upper edges of the dead plates and the air passage is so arranged as to insu e culation of the air along the surfaces of these face plates, cooled metallic surfaces flanl retorts extend to and up distance, the side walls 0 provision is made for cooled sideetructure wind boxes pref- Cir above, the top of the normal zone of clinker formation.

Specifically each brick work side wall ..0 has embedded therein a series of wind boxes 16, jointly extending full length of the furnace, each box being of any suitable length determined according to manufacturing convenience. Each such box may be a casting having solid back, end, and top and bottom walls,,and having a central strengthening partition 16' paralleling the end walls. A baffle plate 17 preferably cast integral with the box parallels its back wall between points separated from the top and bottom walls, and then extends forwardly to, or preferably beyond, the front face of the box affording a projecting flange 17 on which the dead plate structure may find bearing. A front plate 18 extends from the top wall toward, but not to, the lip 17 and is preferably detachably secured as by hooks 19 engaging studs 20 formed on the end walls of the box. Manifestly, this construction affords a tortuous air passage 21 having its intake near the bottom of the box and its outlet near the center of the box front, so that the air in passage therethrough will sweep up the back wall of the box and down its front wall 18.

The dead plate structure 25 specifically shown comprises a plurality of short blocks preferably half as long (in the direction of furnace length) as the wind box sections, as a matter of convenience, each of said blocks having a solid top plate, 26, bottom plate 27, closed sides, and open outer end 28 for communication with the wind box passage, and an inner end provided with tuyere openings 29. Each of such blocks is preferably shaped to rest on the edge of the adjacent retort, with its top wall sloping upwardly and in contact with the face plate 18, and its bottom wall 27 resting on the lip 17 of the wind box construction. It will be apparent that the air channel through the wind box finds a continuation through the channel 30 of the dead plate to the tuyere openings 29, these tuyere openings being preferably arranged in the same general relation to the adjacent retort as are the tuyere openings of the blocks between retorts.

Since the up-sloping plate structures 26 preferably extend, as shown, well above the level f the tops or crests of the main tuyere blocks 15, and the wind-box constructions in the side walls extend thereabove to a level higher than the normal zone of clinker for mation, freedom of feed longitudinally of the extreme retort is practically insured; necessity for hand-cleaning or breaking of clinkers is minimized; and durability and efficiency of the fuel-carrying structure is increased.

Although the current of air sweeping through the tuyeres 29 tends to keep them clean, the force feed may cause some ash accumulation in thetuyeres and in the air passage 30, and to facilitate ready removal of such ash deposits I preferably provide in each block a trap normally closed to form part of the bottom wall structure. 31 indicates an opening in the bottom wall and 32 a trap plate movable to open and close the same. iently be secured as by set screws 33 on a shaft 34 mounted in studs 35 on the wall 27, so that by the operation of a handle 38' the'tops of the main tuyere blocks, each said side plate structure having tuyere-openings therethrough and having an air channel formed therein communicating with the adjacent wind-box and leading'to the tuyereopenings.

2. The combination with the wind chamber and combustion chamber of an underfeed furnace that has a plurality of parallel retorts spaced apart and spaced'from the combustion-chamber walls, along which fuel may be fed, separated by main tuyereblocks the tops of which are in the level of active fuel combustion, of side-plates up- Such trap plates may convensloping from the outer sides of the extreme e retorts toward the combustion chamber side walls to a level higher than the tops of the main tuyere-blocks, said side plates having air channels on their under sides, and wind boxes along the furnace side-walls with which the side plate air channels communicate, said. wind-boxes communicating with said wind chamber and extending above the normal zone of clinker formation.

ber and combustion chamber of an underfeed furnace that has a plurality of parallel retorts spaced apartand spaced from the combustion-chamber walls, .along which fuel may befed, separated by main tuyereblocks the tops of which are in the level of active fuel combustion, of side-plates upsloping from the outer sides of the extreme retorts toward the combustion chamber sidewalls to a level higher than the tops of the main tuyere-blocks, said side plates having 3. The combination with the wind cham I air channels on their under sides, and wind boxes along the furnace side-walls with which the side plate air channels communicate, said wind-boxes comunicatingl with said wind-chamber and exposed to the combustion-chamber above the outer edges of the lip-sloping side plates and extending above the normal zone of clinker formation.

4. In a furnace of the character described, the combination with side walls, retorts, combustion chamber and wind chamber therebelow, said retorts being spaced from the side walls of the combustion chamber, of

. a plate structure spanning from the side retort to the side wall having a tuyere opening adjacent the retort, means forming an air channel extending transversely of the plate to said tuyere opening and communicating with the said wind chamber, said structure having an ash dump opening below and adjacent to said tuyere opening, and

movable means for controlling said dump opening. i

5. In a furnace of the character described, the combination of a fire-box side wall, a retort spaced'therefrom, a combustion chamber above the retort, and a wind-chamber below said retort, of a plate structure. steeply rip-sloping from the retort and spanning therefrom to the side wall and having walls forming an air channel extending transversely of the plate and communicating with said wind-chamber, there being a tuyere opening from said air channel to the combustion space relatively remote from the firebox wall, and an ash dump opening through one of thewalls of said plates adjacent and below the tuyere, a movable closure for said dump opening, and means for operating said closure.

ARTHUR H. BLACKBURN. 

